Most authorities, including Aleinikoff, Tribe and Olson, have concluded that McCain is a citizen by birth under the Common Law and that said citizenship is not derivative but is covered by the "embassador" principle as laid down by Blackstone.

See: Calvin's Case (1608) 2) If you are the child of an "embassador" (elsewhere it is stipulated that this includes the children of Military Officers on duty abroad) you owe Natural Allegiance to the Jurisdiction from which the "embassador" comes.